Electron spin splitting in polarization-doped group-III nitrides

Litvinov, V. I.

doi:10.1103/physrevb.68.155314

Cited by 67 publications

(63 citation statements)

References 35 publications

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“…[18][19][20][21] The Rashba spin splitting due to SIA, which is not expected in wide band semiconductors, in GaN/AlGaN heterostructures is caused by a large piezoelectric effect, 22 which yields a strong electric field at the GaN/AlGaN interface and a strong polarization induced doping effect. 23 Figures 5͑a͒ and 5͑b͒ demonstrate the dependences of the photocurrent on the angle p for positive angle 0 . In Fig.…”

Section: Figmentioning

confidence: 99%

Quantum ratchet effects induced by terahertz radiation in GaN-based two-dimensional structures

et al. 2008

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Section: Figmentioning

confidence: 99%

Quantum ratchet effects induced by terahertz radiation in GaN-based two-dimensional structures

et al. 2008

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“…6,8 Currently, active experimental work on SO properties of microstructures including the wurtzite modifications of InAs, 44 InN, 45 GaN, [46][47][48] etc., is under way, and large SO splittings up to 9 meV have been reported. 47 Following the initial calculations of the band structure of wurtzite-type compounds, 49 more general models have been developed recently, 50,51 and it looks like the band folding in the hexagonal direction ͑resulting from the different size of the elementary cells in the zinc blende and wurtzite lattices͒ plays a role in developing large spin splittings. 52 Therefore, the Hamiltonian Ĥ R will be applied for arbitrary n , n 0.…”

Section: Dmentioning

confidence: 99%

Theory of electric dipole spin resonance in a parabolic quantum well

Éfros

Rashba

2006

Phys. Rev. B

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A theory of electric dipole spin resonance ͑EDSR͒, that is caused by various mechanisms of spin-orbit coupling, is developed as applied to free electrons in a parabolic quantum well. Choosing a parabolic shape of the well has allowed us to find explicit expressions for the EDSR intensity and its dependence on the magnetic field direction in terms of the basic parameters of the Hamiltonian. By using these expressions, we have investigated and compared the effect of specific mechanisms of spin orbit ͑SO͒ coupling and different polarizations of ac electric field on the intensity of EDSR. It is our basic assumption that the SO coupling energy is small compared with all different competing energies ͑the confinement energy, and the cyclotron and Zeeman energies͒ that allowed us to describe all SO coupling mechanisms in the framework of the same general approach. For this purpose, we have developed an operator formalism for calculating matrix elements of the transitions between different quantum levels. To make these calculations efficient enough and to derive explicit and concise expressions for the EDSR intensity, we have established a set of remarkable identities relating the eigenfrequencies and the angles defining the spatial orientation of the quantizing magnetic field B͑ , ͒. Applicability of these identities is not restricted by EDSR and we expect them to be useful for the general theory of parabolic quantum wells. The angular dependences of the EDSR intensity, found for various SO coupling mechanisms, show a fine structure consisting of alternating up and down cusps originating from repopulating different quantum levels and their spin sublevels. Angular dependences of the EDSR intensity are indicative of the relative contributions of the competing mechanisms of SO coupling. Our results show that electrical manipulating electron spins in quantum wells is generally highly efficient, especially by an in-plane ac electric field.

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“…4 A large piezoelectric effect which causes a strong electric field at the Al x Ga 1−x N / GaN interface and the strong polarization induced doping effect, on the other hand, may result in a sizeable Rashba contribution to spin splitting of the band due to spin-orbit interaction ͑ϳ1 meV͒. 5 Indeed a spin splitting of 9 meV was extracted from beatings of Shubnikov-deHaas oscillations in Al 0.25 Ga 0.75 N / GaN heterostructures. 6 However, such beatings were ascribed to magnetointersubband scattering by others.…”

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Demonstration Of Rashba Spin Splitting In GaN-based Heterostructures

Weber¹,

Ganichev²,

Seidl³

et al. 2007

AIP Conference Proceedings

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The circular photogalvanic effect, induced by infrared radiation, has been observed in ͑0001͒-oriented n-GaN low dimensional structures. The photocurrent changes sign upon reversing the radiation helicity demonstrating the existence of spin splitting of the conduction band in k space in this type of materials. The observation suggests the presence of a sizeable Rashba type of spin splitting, caused by the built-in asymmetry at the AlGaN / GaN interface. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.2158024͔ Gallium nitride is a potentially interesting material system for spintronics since it is expected to become ferromagnetic with a Curie temperature above room temperature if doped with manganese.1 Long spin relaxation times observed in this materials are another promising property for possible applications.2 Little is known so far about spin orbit interaction in GaN based heterojunctions like existence of Rashba spin splitting in the band structure which would provide a potential handle for spin manipulation.3 Strong spin-orbit effects are expected to be in narrow-gap materials only. 4 A large piezoelectric effect which causes a strong electric field at the Al x Ga 1−x N / GaN interface and the strong polarization induced doping effect, on the other hand, may result in a sizeable Rashba contribution to spin splitting of the band due to spin-orbit interaction ͑ϳ1 meV͒.5 Indeed a spin splitting of 9 meV was extracted from beatings of Shubnikov-deHaas oscillations in Al 0.25 Ga 0.75 N / GaN heterostructures. 6 However, such beatings were ascribed to magnetointersubband scattering by others.7 On the other hand, the observation of short spin relaxation times was attributed to D'yakonov-Perel mechanism which requires Rashba spin splitting. 8 To investigate the presence of a sizable spin splitting in this material class we investigate the circular photogalvanic effect ͑CPGE͒. 9-11The CPGE as well as k-linear spin splitting of the band structure are only permitted in gyrotropic media. In such materials a linear relation between polar vectors ͑electric current j, quasimomentum q, etc.͒ and axial vectors ͑photon angular momentum, spin, etc.͒ is allowed by symmetry. Both GaN / AlGaN low dimensional structures and bulk GaN belong to the family of wurtzite-type semiconductors which are gyrotropic. As were pointed out in Refs. 12 and 13 in these media the spin-orbit part of the Hamiltonian has the formHere the z axis is directed along the hexagonal c axis and is the vector of Pauli matrices. In bulk wurtzite materials the constant ␣ in the Hamiltonian ͑1͒ is solely due to bulk inversion asymmetry ͑BIA͒. In heterostructures, an additional source of k-linear spin splitting, induced by structure inversion asymmetry ͑SIA͒, exists. It occurs in asymmetric semiconductor heterostructures of any material. 3 If both, bulk and structure asymmetries, are present the resulting coupling constant ␣ is equal to the sum of BIA and SIA contributions to the spin-orbit part of the Hamiltonian. Note that in bulk III-V semiconductors wh...

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Electron spin splitting in polarization-doped group-III nitrides

Cited by 67 publications

References 35 publications

Quantum ratchet effects induced by terahertz radiation in GaN-based two-dimensional structures

Quantum ratchet effects induced by terahertz radiation in GaN-based two-dimensional structures

Theory of electric dipole spin resonance in a parabolic quantum well

Demonstration Of Rashba Spin Splitting In GaN-based Heterostructures

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